Portable bulk storage tank



FIG. 1 is a front elevational view of the portable bulk storage tank showing our new design;

FIG. 2 is a side elevational view thereof, the other side being identical;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a top plan view thereof; and

FIG. 5 is a bottom view thereof. 

The ornamental design for portable bulk storage tank, as shown and described. 